1. Field of the Invention
The present invention generally relates to a technology for processing images and outputting the processed images.
2. Description of the Related Art
The development of line sensor reading devices including charged-coupled devices (CCDs) and writing devices that use laser beams for writing has resulted in the development of digital copiers from traditional analog copiers.
Besides copying, a typical digital copier is equipped with various other functions such as scanning, printing, and facsimile. Hence, the digital copier is sometimes referred to as a digital multifunction product (MFP).
By connecting the MFP to a network, image data that is stored in the storage device, such as a hard disk drive (HDD), of an MFP can be transmitted to various other devices such as copiers, facsimile devices, and personal computers (PC) through the network. Because of the versatility of MFPs, the MFPs are being used in offices in a diversified manner.
For example, a small-sized MFP can be installed alongside a PC on a working desk to enjoy from the PC the functions of copying, facsimile, printing, and scanning available on the MFP. A middle-sized MFP can be shared by two or more departments or sections of an office. Such a use makes it possible to achieve a certain degree of productivity along with the use of functions like sorting, punching, and stapling provided in middle-sized MFPs. A large-sized multifunction MFP with high productivity and high quality can be used in departments where copying amounts to a large part of business, or in organizations that mainly deal with the business associated with copying.
Thus, an MFP of an appropriate class (size and functions) can be used depending on the use of the MFP. While all MFPs have some common functions, there are certain class-dependent functions. For example, large-sized MFPs have functions such as punching, stapling, and folding and electronic filing along with usual copying function. Small-sized MFPs often have enhanced Internet-FAX or PC-FAX services, and to perform high-quality image printing on dedicated paper for personal use.
On the other hand, along with the development of networking, there has been a desire that MFPs perform distributed processing through the network and share data between each other. For example, to print a large amount of data, there is a desire to distribute the data among some or all of the MFPs connected through the network to reduce the overall printing time.
The conventional systems that were built and sold prior to such diversified MFPs have a fixed set of functions necessary for each particular class only. As the importance of information values in business has been already recognized, the need is to not only transmit fast, accurate, and reliable information, but also to transmit it in an easy-to-understand and effective manner. Speed-up and diffusion of communication technology, development of large-capacity, low-cost, and small-sized memory devices, and enhancement in the performance of PCs have all resulted in providing a new function that efficiently handles information having digital data. Accordingly, MFPs handling digital image data are also required to provide and integrate new functions.
In the meantime, a document to be copied or scanned has various characteristics. In the conventional technology disclosed for example in Japanese Patent Applications Laid-open No. H9-134438 and H10-42130), the characteristic part of an image data of a document is extracted, and filter processing, color correction processing, and halftone processing are performed on the image data based on the extracted characteristic part.
According to another conventional technology disclosed for example in Japanese Patent Applications Laid-open No. 2001-223828, scanned image data and a unique signal that indicates the characteristic area of the scanned image data are stored in the HDD, and an appropriate image processing is performed depending on the output application.
However, in the conventional image processing apparatuses, the scanned image data reflects the features of the scanner itself. Hence, to share the data with other apparatuses, it is necessary, for example, to transmit to an image processing apparatus the features, i.e., the profile of the scanner.
It is common to perform irreversible compression, such as JPEG, when storing image data. When a document is a dot image, however, the compression ratio is poor, which results in unintended moire interference, thereby degrading the image quality. Moreover, sometimes noise or blank data, which is unrecognizable by the viewer, occur in image data read by a reading device. The noise or the blank data is another cause for poor compression ratio, which in turn leads to degraded image quality.